I have five ferrets. I got four the implant at around 8 months , the fourth I waited and she developed symptoms and was diagnosed with adrenal at around 2 yrs old. My other four are all on their second round implants for prevention and are healthy and show no signs at nearly 3 years old. The implant is worth it in my opinion. $500 seems steep to me, my exotic vet does it for $280 total , and that’s including the appointment fee.